Changeset 54872 in vbox

Timestamp:

Mar 20, 2015 2:16:39 PM (10 years ago)

Author:

vboxsync

Message:

threadctxhooks-r0drv-linux.c: Looks like 3.19 stopped restoring kernel RFLAGS during context switches, so we need to handle RFLAGS.AC our selves.

File:

• trunk/src/VBox/Runtime/r0drv/linux/threadctxhooks-r0drv-linux.c (modified) (4 diffs)

trunk/src/VBox/Runtime/r0drv/linux/threadctxhooks-r0drv-linux.c

@@ -5 +5 @@
 
 /*
- * Copyright (C) 2013 Oracle Corporation
+ * Copyright (C) 2013-2015 Oracle Corporation
  *
  * This file is part of VirtualBox Open Source Edition (OSE), as
@@ -72 +72 @@
     /** The reference count for this object. */
     uint32_t volatile           cRefs;
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(3, 1, 19) && defined(RT_ARCH_AMD64)
+    /** Starting with 3.1.19, the linux kernel doesn't restore kernel RFLAGS during
+     * task switch, so we have to do that ourselves. (x86 code is not affected.) */
+    RTCCUINTREG                 fSavedRFlags;
+#endif
 } RTTHREADCTXINT, *PRTTHREADCTXINT;
 
@@ -101 +106 @@
 
 #if defined(RT_ARCH_AMD64) || defined(RT_ARCH_X86)
-    clac();
     ASMSetFlags(fSavedEFlags);
+# if LINUX_VERSION_CODE >= KERNEL_VERSION(3, 1, 19) && defined(RT_ARCH_AMD64)
+    pThis->fSavedRFlags = fSavedEFlags;
+# endif
 #endif
 }
@@ -128 +135 @@
     Assert(pThis->fRegistered);
 
-
     pThis->pfnThreadCtxHook(RTTHREADCTXEVENT_RESUMED, pThis->pvUser);
 
 #if defined(RT_ARCH_AMD64) || defined(RT_ARCH_X86)
-    clac();
+# if LINUX_VERSION_CODE >= KERNEL_VERSION(3, 1, 19) && defined(RT_ARCH_AMD64)
+    fSavedEFlags &= ~RT_BIT_64(18) /*X86_EFL_AC*/;
+    fSavedEFlags |= pThis->fSavedRFlags & RT_BIT_64(18) /*X86_EFL_AC*/;
+# endif
     ASMSetFlags(fSavedEFlags);
 #endif